A tray under the freezer is there for defrosting and for any other reason that requires dripping water to be caught. Some models come with a built-in tray to catch water drips, but if your model does not have a tray, you'll need to get one, especially if you find standing water on your floor.
Freezers require a tray underneath or inside the appliance to catch dripping water. When in defrost mode, the freezer releases water from the melted ice. Any time the temperature of the freezer drops, such as during a power outage or a operation malfunction, the freezer might leak water. A tray, whether built-in or freestanding, catches the water to prevent flooding, damaged flooring or other ruined building materials.
Some freezers, especially newer models, have a built-in defrosting tray. It can sit within the freezer or at the bottom under the appliance. It usually slides in and out for easy removal to empty it. Before starting the defrost cycle, empty the tray if it has any water in it. During the defrosting cycle, check the tray often. Empty it before it's completely full to prevent it from overfilling. Wash the tray after the defrost cycle with a solution of water and baking soda. Rinse the tray and dry it before replacing it in the freezer.
For a freezer that doesn't have a drip tray or a freezer that leaks water around the installed tray, place a drip tray underneath the appliance. Drip trays are also marketed under the names "overflow tray" or "defrost pan." They are available from appliance parts stores. In a pinch, use a shallow baking pan or other container that fits under the freezer. As with built-in trays, empty the pan often to prevent overflow.
Warnings and Tips
Freestanding water around the freezer can pose an electrocution risk. On self-defrosting models, you usually don't need to remove the tray. The water is typically directed to a system where heat dries the water. Collect excess water from the bottom of a freezer with a sponge to prevent overflowing. Do not place a freezer where temperatures reach more than 110 degrees Fahrenheit or near a heat source such as a heat register or in direct sunlight. The freezer is unable to maintain proper cooling temperatures in high temperatures.